Starter drive for internal combustion engine



Jan. 24, 1967 P. TOULIER 3,299,719

STARTER DRIVE FOR INTERNAL COMBUSTION ENGINE Filed April 6, 1965 3Sheets-Sheet l STARTER DRIVE FOR INTERNAL COMBUSTION ENGINE Filed April6, 1965 P. TOULIER Jan. 24, 1967 3 Sheets-Sheet 2 Fig. 8

1967 P. TOULIER 3,299,719

STARTER DRIVE FOR INTERNAL COMBUSTION ENGINE Filed April 6, 1965 3Sheets-Sheet 15 United States Patent 3,299,719 STARTER DRIVE FORINTERNAL CGMIBUSTIQN ENGINE Pierre Toulier, Ville dAvray, France,assignor to Societe Anonyme D.B.A., Paris, France, a company of FranceFiled Apr. 6, 1965, Ser. No. 446,028 Claims priority, applicationFrance, Apr. 8, 1964, 970,204 12 Claims. (Cl. 74-7) The presentinvention relates to a starter drive for internal combustion engine inwhich the coupling member, such as pinion cooperating with a toothedwheel, is operatively connected by a free wheel, or any similarunidirectional clutch device, to a sleeve member threaded on the shaftof the starting motor.

This device is characterized in that means are associated with saidsleeve member to create a friction torque opposing the rotation of saidsleeve thereby causing the movement of said pinion toward said toothedwheel and then causing said pinion to stay in meshing engagementtherewith during the starting of the internal combustion engine and inthat resilient means are provided to urge as a unit, the pinion, thefree wheel and the sleeve member back into a position in which thepinion is disengaged from the toothed wheel. The friction torque appliedto the sleeve member by the aforesaid friction means has, according tothe invention, a value which is larger than that of the friction torqueapplied to the sleeve member in opposition by the unclutchedunidirectional device when the internal combustion engine is started,the remaining differential torque being adapted to generate incooperation with the threaded operative connection between the sleevemember and the shaft of the starting motor, an axial thrust toward saidtoothed wheel superior to the thrust exerted in the opposite directionby said resilient returning means.

The device broadly defined hereinabove presents a peculiar advantagewith respect to the known device (called positively operated starter)since its operation is controlled by a simple switching on of theelectric starting motor without the necessity of providing a specialcontrol means, such as a solenoid for instance, for engaging the pinionwith the toothed wheel before energizing the electric starting motor.

The device of the invention avoids premature disengagement of the pinionwhich occurs frequently in intertial starting devices wherein as theresult of ignition in one cylinder alone, the pinion may be kicked outof the toothed wheel.

The device of the invention presents advantages in comparison to thosedevices known in the trade under the name FOLO-TI-IRU both from thepoint of view of simplicity of construction as well as reduction insize. Furthermore it achieves an increased reliability in that thereturn of the pinion to its retracted position no longer depends upondelicate and costly centrifugal de-clutching.

Other characterizing features of the invention will appear in thefollowing specification in which reference is made to the accompanyingdrawings in which:

FIG. 1 shows a starting apparatus according to the invention with itspinion out of the toothed wheel.

FIG. 2 shows the device of FIG. 1 in starting position i.e. with itspinion meshing with the toothed wheel.

FIG. 3 is a partial cross-section view taken along line 3-3 of FIG. 2showing more particularly the friction means cooperating with the sleevemember of the starting device.

FIG. 4 shows a friction washer used to constitute the friction means.

FIG. 5 shows in partial cross-section a starting device according toanother embodiment of the invention com- Patented Jan. 24, 1967 prisingthe use for a friction plate which is laterally guided.

FIG. 6 shows resilient returning means of the unit comprising the sleevemember and the pinion of the embodiment of FIG. 5.

FIGS. 7 and 8 show in longitudinal cross-section, with parts brokenaway, a starting device according to another embodiment of theinvention, in .the inactive and in the active positions respectively.

FIG. 9 is a transversal cross-section of the device of FIGS. 7 and 8passing through the rocking axis of the fork and between the twofriction plates.

FIG. 10 is a cross-section along the line 1010 of FIG. 9.

FIG. 11 is a cross-section along line 11--11 of FIG. 10.

FIG. 12 is a perspective view of the spring biasing the fork of thedevice of FIGS. 7 and 8.

FIGS. 13 and 14 show in longitudinal cross-section, with parts brokenaway, a starting device according to still a further embodiment of theinvention, FIG. 13 showing this device in the inoperative state and FIG.14

' the same device in the operative state.

FIG. 15 is a cross-section along line 1515 of FIG. 14.

A starting device for internal combustion engine according to theinvention will be described hereinafter with reference to FIGS. 1 to 4.In these figures, reference numeral 10 designates the shaft of thestarter drive; reference numeral 12 designates a pinion which is adaptedto freely slide on the shaft 10 and which is connected by means of afree wheel roller clutch, disc clutch or like unidirectional clutchdevice 14, to a threaded sleeve member 16 adapted to be threaded on along pitch thread 18 of the shaft 10 of the starter drive. The sleevemember 16 is provided with a fiat surface 20. On the sleeve member 16are slipped on two flat washers 22 and 24 comprising a central openingthe shape of which is such that said washers 22 and 24 cooperate withthe sleeve 16 and the fiat surface 20 thereof to be driven into rotationby said sleeve 16. Between the washers 22 and 24 is pressed 3 plate 26comprising diametrally opposed lugs 27 engaging slots 29 provided atboth ends of a fork 31 pivotally mounted by its upper portion about apin 33 solid with the bearing forming portion of the devices body. Acompression spring 35 acts upon the fork 31 to urge plate 26 in contactwith washer 22, the latter being itself applied upon a snap-ring 30fastened on sleeve member 16. Plate 26 comprises a circular openinghaving in diameter slightly larger than the diameter of sleeve 16 sothat said plate may freely rotate about said sleeve member. Acompression spring 28 is provided between the shoulder formed by freewheel 14 and sleeve member 16, and the washer 24 to urge said washer 24against plate 26.

It is easily understood that a convenient choice of thespring 28 causingthe plate 26 to be pressed between washers 22 and 24 provides thefriction means restraining the rotation of sleeve member 16. The thrustof spring 28 is so chosen that a friction torque applied by the plate 26to the sleeve member 16 is .higher than the resisting torque proper tofree wheel device 14 when the latter is in its unclutched state, pinion12 being driven by the toothed wheel 40 of the internal combustionengine.

The compression spring 35 acting upon fork 31 takes support on thebottom of a cavity provided in the bearing of the electric startingmotor and exerts upon fork 21 a thrust which is sufiicient to returnbackward and maintain in inoperative position the Whole of the slidingcomponents cooperating with the sleeve member 16 when the rotary speedof the rotor shaft 16 is less than a given value as will be explainedhereinafter when the operation of the device will be described.

A stop ring 11 axially positioned on shaft by means of a snap ring 13 isused to limit the axial stroke of the plurality of components slidingwith the sleeve member 16 in a position in which the pinion 12 mesheswith the toothed wheel 40.

The operation of the device described hereinabove is the following:

The electric starting motor being energized, the splines 18 of shaft 10cooperate with the corresponding splines of the sleeve member 16, therotary motion of which is restrained by the friction effect of plate 26on washers 22 and 24 pressed against said plate. It results therefromthat the unit constituted by pinion 12-free wheel 14 and sleeve member16 is pushed to mesh with the toothed Wheel 40 until pinion 12 abutsstop member 11. It is to be noted that the travel of pinion 12 towardtoothed wheel 40 is obtained even though the inertia of the plurality ofcomponents operatively connected to sleeve member 16 is low since thistravel movement is obtained because of the friction created upon thesleeve member by plate 26. The provision of long pitch splines (thispitch can be, for instance, of the order 5 to 20 times the diameter ofthe shaft) permits obtaining a quick axial travel of pinion 12 whichthus meshes with toothed wheel 40 in a very short period of time at arotary speed which is sufficiently low. Thus can be avoided a failure ofpinion 12 or toothed wheel 41!. It is to be noted that after the teethof pinion 12 have meshed with the teeth of toothed wheel 40, theinternal combustion engine being still unstarted, pinion 12 isrestrained in rotation by toothed wheel 40 and its axial travel in theteeth of the toothed wheel continues Without any further use of thefriction effect of plate 26 against sleeve member 16 which hasfacilitated the initial axial travel.

While the starting motor .is kept rotating, pinion 12 drives theinternal combustion engine by means of toothed wheel 40. If after acertain time during which the toothed wheel 40 is driven by pinion 12the internal combustion engine cannot be started, it is obvious thatwhen the operator cuts off the electric supply to the starting motor,the plurality of parts comprising pinion 12 freewheel 14 and sleevemember 16 are returned backward under the action of spring 35 pushingupon fork 31 (toward the right when considering the drawing) until thesleeve member 16 is brought in abutment against shoulder 41 of shaft 10,this corresponding to the retracted posi tion of the pinion .12 (FIG.1).

When the internal combustion engine is starting whether after anisolated explosion or a correct starting, the toothed wheel 40 isdriving pinion 12 at a rotary speed which can be higher than the speedthat has been communicated to said pinion by the electric startingmotor. In this case, the free wheel 40' operates to avoid an overspeeddriving of the starting motor by the internal combustion engine.

So long as the operator maintains the electric supply circuit of thestarting motor switched on, the latter keeps driving the sleeve member16 and the portion 14a of free wheel 14 solid therewith. Since theinternal combustion engine rotates, the toothed wheel 40 is drivingpinion 12 (and the portion 14b of the free wheel solid with said pinion)in the same direction as portion 14a but at a higher rotary speed (thefree wheel being de-clutched). The de-clut-ched free wheel 14 transmitsto sleeve member 16 a friction torque which tends to override the torquegenerated by plate 26 together with washers 22 and 24 and thus to movesleeve member 16 in a direction corresponding to the disengagement ofpinion 12. The resilient means (spring 35) acting upon the sleeve member16 through fork 31 and plate 26 assists this disengagement. Thecondition that has to be fulfilled in order so that pinion 12 remainsengaged in toothed wheel 40 can thus be expressed as follows: theresisting torque that the unclutched free wheel transmits to the sleevememher (for a given speed of pinion driven by toothed wheel) must be lowenough when compared to the friction torque generated by plate 26 actingon the sleeve member 16 (at a given speed of the electric motor) so thatthe resulting torque applied to sleeve member .16 generates (bycooperation of the splines of sleeve member 16 with the correspondingsplines 18 of shaft 10) an axial thrust which is opposed (and higher inabsolute value) to the one exerted by spring 35 upon sleeve member 16.It is to be noted that the friction forces in the free wheel depend onthe construction, and the same is also true of the friction coeflicientexisting between the splines of the sleeve member and the splines of theshaft. Furthermore, the strength of the spring 35 is so chosen that thelatter opposes an undesired forward travel-of pinion 12 resulting fromvibrations and causes the retraction of said pinion after the engine hasbeen started and the pinion is disengaged. It results from the foregoingthat particular attention should be paid to the value of the frictionforces applied by Washers 22 and 24 to plate 26 i.e. to the strength ofspring 28, to the area of the washers and to the nature of the contactsurfaces to maintain pinion 12 in engagement in toothed wheel 40 whenthe starting motor is energized for given starting conditions of theinternal combustion engine. It is necessary to obtain that the frictiontorque applied by plate 26 to sleeve member 16 for a rotary speed of theelectric starting motor near the speed obtained in unloaded condition atthe minimum voltage remains higher than the resisting torque transmittedby the free wheel with a positive difference such that the axial thrustof the sleeve member opposes the thrust of the resilient returning means(spring 35, fork 31), these conditions can be fulfilled even for a highrotary speed of toothed wheel 40.

After the internal combustion engine has been started, the operatorswitches off the electric starting motor, the resisting torque of thefree Wheel 14 becomes preponden ant and the unit comprising pinion12-free Wheel 14 and sleeve member 16 is returned in disengagedposition. This motion is first caused by the combined action of the freewheel (causing the threading of the splined sleeve member 16 on thesplines of shaft 10) and of fork 31 which is pushed by its spring 35.When pinion 12 is out of toothed wheel 40, the return motion iscontinued under the exclusive action of spring 35 as already explainedin the case of the backward motion following a refusal to start of theinternal combustion engine.

It is obvious that it is possible to use other static restrainingfriction means applied upon sleeve member 16 than those comprisingwashers 22 and 24 pressed against plate 26 and also other resilientreturning means than fork 31 urged by its spring 35.

In another embodiment corresponding to FIGS. 5 and 6, the friction platehas been given a shape such that its lateral lugs cooperate with lateralguiding means solid with the body of the electric motor thus permittingan axial movement of the sleeve member While restraining the rotationthereof. In FIG. 5, there is shown a plate 50 the lugs 52 of whichcomprise slots 54 encompassing longitudinal ribs 56 provided on theinner Walls of a bearing forming element 58 parallel to the axis ofshaft 60. The mounting of plate 50 on the sleeve member 62 betweenfriction washers (not shown) is similar to the mounting that has beendescribed hereinabove with reference to plate 26 on sleeve member 16.

The return means of sleeve member 62 in the present embodiment couldobviously act upon plate 50, however as shown in FIG. 6 there has beenprovided, a helical compression spring 63 on shaft 60 to urge pinion 64of the device in a direction corresponding to the disengagement thereof.Spring 63 takes support on an end stroke stop 66 comprising a recess 68adapted to receive such spring when pinion 64 engages said stop 66 afterhaving meshed with toothed Wheel 70.

The starting apparatus comprising the friction means including plate 50and resilient returning means such as spring 63 operates obviously in amanner similar to the device described hereinabove with reference toFIGS. 1 to 4 in which have been shown other types of friction means andreturning means.

The two other embodiments that will be now described comprise manyimprovements having particularly in view to avoid and compensateclearances between the different parts in relative motion which isparticularly important in devices of this kind.

The starter drive represented in FIGS. 7 to 9 generally comprises a body80 including an electric starting motor of which has been represented inpartial'crosssection, the statorat 82 and the rotor at 84. Rotor 84 hasthe forward portion of its shaft 86 which is received in the bearingforming and 88 of body 80, between the bearing forming portion 88 andthe rotor 84, the shaft 86 comprises a cylindrical portion 90 and a longpitch threaded portion 92. On the cylindrical portion 90 is slidably androtatably mounted a pinion 94 with interposition of a coaxial sleeve 96.On the threaded portion 92 is threaded a sleeve member 98,

the inner wall of which comprises splines cooperating with thecorresponding splines of portion 92. As shown in FIGS. 7 and 8, therearward portion 97 of pinion 94 and the forward portion 100 of sleevemember 98 constitutes the inner and the outer races respectively of afree wheel generally designated by reference numeral 102. Free wheel 102is of a known type, there has been represented at 104 the rollersthereof and at 106 its housing crimped upon the portion 97 of pinion 94and upon the portion 100 of sleeve member 98 respectively. Free wheel102 comprises an internal compression spring 108 biasing parts 97 and100 away from one another, said parts 97 and 100 being in engagement, asshown in FIG. 8, when the device being in operative condition, pinion 94which meshes with the corresponding toothed wheel 112 is in abutmentagainst a ring 114 fastened on portion 90 of shaft 86.

The means used to generate the friction torque applied to sleeve member98 on the one hand and the resilient returning means urging the pinion94 out of toothed wheel 112 will be now described with reference toFIGS. 7 to 12.

In order to generate the friction torque applied to sleeve member 98 twowasher-like rings 116 and 117 have been slipped on said sleeve member.These rings which are similar to those shown in plan view on FIG. 4comprise a central cut out portion comprising a rectilinear edgecooperating with a flat surface 120 machined on sleeve member 98 with aview to permitting the rings 116 and 117 to be rotatably driven by saidsleeve member. Ring 116 is in abutment against a snap ring 124 insertedin a groove provided in sleeve member 98. Ring 117 is applied on thelateral portion of a rubber O-ring 126 extending out of an annularhousing 128 in engagement with a shoulder 130 on sleeve member 98.Between rings 116 and 117 is located a friction plate forming unitcomprising two annular elements 132 and 133.

Elements 132 and 133 comprise diametrally opposed lugs 134 ofsemi-cylindrical shape, constituting half shells as shown in FIG. 11.The shells of the annular element 132 have their concavities located infront of the concavities of element 133 so that they may receivefinger-like, substantially cylindrical extensions 136 of a forkgenerally designated by reference numeral 138.

Fork 138 is slidably mounted about a pin 140 fastened to the starterdrive body 80, pin 140 passing through a slot 142 which is open in thepresent example.

Upon fork 138 are acting resilient return means for the unit comprisingthe sleeve member, the free wheel and the pinion. In the presentembodiment said returning means consist of a spring 144. This spring144, shown in perspective view in FIG. 12, is made of a steel wire theends of which 145, 146 take support on the inner wall of body while itsmedian portion 147 encompasses the lever forming portion of fork 138. Asshown in FIG. 9, the turns of springs 144 provide a good resilientcontact between fork 138 and the walls of body 80; thus are avoided thelateral movements of the fork.

The operation of the device which has just been described is similar tothe one of the device described with reference to FIGS. 1 to 3.

The device according to the embodiment of FIGS. 7 to 12 presents manyadvantages from a technical point of view resulting from the suppressionor.compensation of the clearances between co-operating elements of thestarter drive. I

The provision of shells 134 on the plates 132-134 resiliently urged onetoward the other by the O-ring 126 permits a perfect cooperation withcompensation of the play between the finger-like extensions 136 and theplates 132 and 133. With this arrangement, as soon as the rotor 86 ofthe starting motor has been energized, plates 132 and 133 slide with agiven friction effect on rings 116117 without being driven in rotationby the latter and it results therefrom that the unit comprising pinion94, free wheel 102 and sleeve member 98 is immediately axially driven ina direction corresponding to the engagement of pinion 94 into toothedwheel 112. Pinion 94 engages toothed wheel 112 with a rotary speed whichis substantially less than if plates 132-133 had been capable of acertain angular motion.

An important improvement is also obtained because of the use of therubber-ring 126 which is exactly received by housing 128 thus avoidingan extrusion of the elastomeric matter toward the outside of saidhousing. In efiect, the outwardly portion of the rubber ring 126 isapplied upon friction ring 118 and the friction forces applied by thetwo rings 116-117 upon plate 132-133 are uniformly distributed, thefriction torque being thus constant whatever the angular position of thesleeve member with respect to plate 132-133 may be.

In FIGS.v 13 to 15 has been represented still another embodiment of theinvention according to which the starter drive comprises a body 150including a stator 152 in which is rotated a rotor 154 comprising ashaft 156 on which is slidably and rotatably mounted a unit comprising apinion 158, a free wheel 160 and a threaded sleeve member 162. Thesplines of the sleeve member 162 cooperate with corresponding long pitchsplines of shaft 166. Upon helical motion of the above mentioned unit,pinion 168 engages a toothed wheel 164 driving in rotation an internalcombustion engine. At the end of its stroke pinion 168 is brought inabutment against a ring 166 fixed to shaft 156.

Sleeve member 162 passes through a transversal plate 168 solid with body150. A compression spring 170 is slipped on sleeve member 162, saidspring takes support on plate 168 and on a ring 172 which is urgedtoward the lateral face of a friction plate 174 which is in contact byits other face with a ring 173, the latter being in abutment against asnap ring 176 inserted in a groove provided in sleeve member 162. Rings172 and 173 are similar to rings 116417 of the embodiment of FIGS, 1 to11, they cooperate with a flat surface 178 machined on the sleeve member162 with which they are driven in rotation.

Friction plate 174 is provided with diametrically opposed lugs 180provided with notches cooperating with longitudinal ribs 182 provided onthe inner walls of body 150 parallel to the axis of the shaft of rotor156. With such an arrangement plate 174 is capable of axialdisplacements whereas its rotation is forbidden.

In the device that has just been described with reference to FIGS. 13 to15, the means that are used to apply a friction torque to sleeve member162 consist of a plurality of parts comprising rings 172-173 and plate174. Rings 172-173 are urged against plate 174 under the action of thespring 170 which also plays the role of pinion returning means.

The strength of the compression spring 170 is of course carefullycalculated as well as the values and the nature of the surfaces ofcontact between the rings and the plate upon which they are biased bythe spring.

The operation of the device of FIGS. 13 to 15 is similar to the one ofthe other devices which have been described hereinabove.

What is claimed is:

1. A starter drive for starting an internal combustion engine comprisinga driving motor having a shaft, and a body, a sleeve member threaded onsaid shaft, a driving pinion adapted to mesh with an engine flywheel, aunidirectional clutch arranged to transmit torque from said sleevemember to said pinion, resilient returning means biasing said pinion,clutch and sleeve member axially away from said toothed wheel, frictionmeans acting upon said sleeve member to oppose rotation of said sleevemember with said shaft, the torque applied by said friction means tosaid sleeve member being large enough to cause said pinion to bemaintained in meshed engagement with said toothed wheel even when saidclutch is in its de-clutched state.

2. A starter drive as claimed in claim 1 wherein said friction meansacting upon said sleeve member comprise of at least one non-rotatableplate means resiliently in friction engagement with at least onelining-forming washer rotatable with said sleeve member.

3. A starter drive as claimed in claim 2 wherein said resilientreturning means comprises a helical compression spring urging saidpinion away from said toothed wheel.

4. A starter drive as claimed in claim 2 wherein said resilientreturning means comprise a resiliently biased fork carrying saidnon-rotatable plate means.

5. A starter drive as claimed in claim 4 wherein said plate meanscomprise two friction plates slipped on said sleeve member, saidfriction plates comprising diametrally opposed half shells adapted tocooperate with finger-like extensions of said fork.

6. A starter drive as claimed in claim 5 wherein said two frictionplates are squeezed between two washers rotatable with said sleevemember said Washers being urged one toward the other by resilientlycompressed means.

7. A starter drive as claimed in claim 6 wherein said resilientlycompressed means comprises an O-ring located in an annular housing thebottom of which takes support upon a shoulder provided on said sleevemember.

8. A starter drive as claimed in claim 4 wherein said fork is rockedabout a pin fixed to the body of said motor passing through a slot madein the lever forming part of said fork.

9. A starter drive as claimed in claim 1 wherein said unidirectionalclutch comprises two race-forming coaxial elements solid with saidpinion and said sleeve member respectively, roller means between saidelements and a coaxial compressing spring urging the two elements awayfrom one another.

10. A starter drive as claimed in claim 1 wherein said friction meanscomprise a stop forming snap ring on said sleeve member, a first washerrotatable with said sleeve member engaging said snap ring, a slidablebut non rotatable plate in friction engagement by one of its faces withsaid first washer, a second washer rotatable with said sleeve member infriction engagement with the other face of said plate and a compressionspring taking support on a part solid with a portion of the body of saidmotor to urge said second washer toward said plate.

11. A starter drive as claimed in claim 10 wherein said plate comprisesradially extending lugs cooperating with the inner walls of the body ofsaid motor thereby preventing the rotation'of said plate whereas thelatter is freely .slidable in said body.

12. A starter drive as claimed in claim 11 wherein said' plate comprisestwo lugs diametrally opposed provided with notches cooperating withaxially extending ribs provided on the inner wall of the body of saidmotor.

References Cited by the Examiner UNITED STATES PATENTS 1,815,047 7/1931Burton 747 MILTON KAUFMAN, Primary Examiner.

1. A STARTER DRIVE FOR STARTING AN INTERNAL COMBUSTION ENGINE COMPRISINGA DRIVING MOTOR HAVING A SHAFT, AND A BODY, A SLEEVE MEMBER THREADED ONSAID SHAFT, A DRIVING PINION ADAPTED TO MESH WITH AN ENGINE FLYWHEEL, AUNIDIRECTIONAL CLUTCH ARRANGED TO TRANSMIT TORQUE FROM SAID SLEEVEMEMBER TO SAID PINION, RESILIENT RETURNING MEANS BIASING SAID PINION,CLUTCH AND SLEEVE MEMBER AXIALLY AWAY FROM SAID TOOTHED WHEEL, FRICTIONMEANS ACTING UPON SAID SLEEVE MEMBER TO OPPOSE ROTATION OF SAID SLEEVEMEMBER WITH SAID SHAFT, THE TORQUE APPLIED BY SAID FRICTION MEANS TOSAID SLEEVE MEMBER BEING LARGE ENOUGH TO CAUSE SAID PINION TO BEMAINTAINED IN MESHED ENGAGEMENT WITH SAID TOOTHED WHEEL EVEN WHEN SAIDCLUTCH IS IN ITS DE-CLUTCHED STATE.